In the context of pattern formation, the Langevin/Fokker–Planck
approach has a long history, dating back to the 1970's when it was
applied to convecting systems [1]}. Noise of thermal
origin is however extremely weak so that the region of parameter space
where the system is sensitive to this noise is exceedingly narrow
[2]} and nontrivial effects can be observed only in very specific
conditions [3]}. When applying the approach to the description
of the bifurcation from featureless turbulence to pattern in shear flows,
Prigent et al. [4]} implicitly took for granted
that the noise intensity was an adjustable parameter linked to the turbulent background at \(R>R_{\rm t}\) . Here we extend the analysis started in
[5]} within this conceptual framework, the subject of §,
and analyse simulation results presented in §REF  in the light of this
theory. We conclude in § by discussing how well this approach
is suited to describe mode competition and intermittent re-entrance of
featureless turbulence [6]}, [5]} and, more generally, how the
noisy temporal dynamics of coherent modes can hint at the
spatio-temporal nature of transitional wall-bounded flows and explain
the exponentially decreasing probability distributions of residence
times or decay times often observed in this field [8]}.
